Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|URL: http://dwm.suckless.org/patches/swapfocus
|This patch makes it possible to switch focus with one single shortcut (alt-s)
|instead of having to think if you should use alt-j or alt-k for reaching the
|last used window.
|
|diff -r ec4baab78314 dwm.c
|--- a/dwm.c	Mon Dec 19 15:38:30 2011 +0100
|+++ b/dwm.c	Fri Apr 06 08:23:42 2012 +0200
--------------------------
Patching file dwm.c using Plan A...
Hunk #1 succeeded at 224.
Hunk #2 succeeded at 254.
Hunk #3 succeeded at 1677.
Hunk #4 succeeded at 1785.
Hunk #5 succeeded at 2127.
done